Analysis of soil carbon transit times and age distributions using network theories
Abstract
The long-term soil carbon dynamics may be approximated by networks of linear compartments,
permitting theoretical analysis of transit time (i.e., the total time spent by a molecule
in the system) and age (the time elapsed since the molecule entered the system) distributions.
We compute and compare these distributions for different network. configurations,
ranging from the simple individual compartment, to series and parallel linear compartments,
feedback systems, and models assuming a continuous distribution of decay constants.
We also derive the transit time and age distributions of some complex, widely used
soil carbon models (the compartmental models CENTURY and Rothamsted, and the continuous-quality
Q-Model), and discuss them in the context of long-term carbon sequestration in soils.
We show how complex models including feedback loops and slow compartments have distributions
with heavier tails than simpler models. Power law tails emerge when using continuous-quality
models, indicating long retention times for an important fraction of soil carbon.
The responsiveness of the soil system to changes in decay constants due to altered
climatic conditions or plant species composition is found to be stronger when all
compartments respond equally to the environmental change, and when the slower compartments
are more sensitive than the faster ones or lose more carbon through microbial respiration.
Copyright 2009 by the American Geophysical Union.
Type
Journal articlePermalink
https://hdl.handle.net/10161/3995Published Version (Please cite this version)
10.1029/2009JG001070Publication Info
Manzoni, S; Katul, GG; & Porporato, A (2009). Analysis of soil carbon transit times and age distributions using network theories.
Journal of Geophysical Research: Biogeosciences, 114(4). pp. G04025. 10.1029/2009JG001070. Retrieved from https://hdl.handle.net/10161/3995.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
Collections
More Info
Show full item recordScholars@Duke
Gabriel G. Katul
Theodore S. Coile Distinguished Professor of Hydrology and Micrometeorology
Gabriel G. Katul received his B.E. degree in 1988 at the American University of Beirut
(Beirut, Lebanon), his M.S. degree in 1990 at Oregon State University (Corvallis,
OR) and his Ph.D degree in 1993 at the University of California in Davis (Davis, CA).
He is currently the Theodore S. Coile Professor of Hydrology and Micrometeorology
at the Nicholas School of the Environment and the Department of Civil and Environmental
Engineering at Duke University (Durham,
Amilcare Porporato
Adjunct Professor in the Department of Civil and Environmental Engineering
Amilcare Porporato earned a Master Degree in Civil Engineering (summa cum laude) in
1992 and his Ph.D. in 1996 from Polytechnic of Turin. He was appointed Assistant Professor
in the Department of Hydraulics of the Polytechnic of Turin, and he moved to Duke
University in 2003, where he is now Full Professor in the Department of Civil and
Environmental Engineering with a secondary appointment with the Nicholas School of
the Environment.
In June 1996, Porporato received the Arturo Parisatti
Alphabetical list of authors with Scholars@Duke profiles.

Articles written by Duke faculty are made available through the campus open access policy. For more information see: Duke Open Access Policy
Rights for Collection: Scholarly Articles
Works are deposited here by their authors, and represent their research and opinions, not that of Duke University. Some materials and descriptions may include offensive content. More info